Visual content, such as images or video, can be provided in a range of different colour spaces. Examples of colour spaces are YUV 420, YUV 444 and RGB 444. In a YUV colour space there is a luminance (Y) component and two chrominance components (U, V). Colour spaces can differ in the amount of data that is used to encode the colour (chrominance) components of the signal.
The Human visual system (HVS) is more sensitive to variations in brightness than colour. Some colour space coding schemes use this property to reduce the amount of data used to encode colour components of the image. For example, in a YUV 420 colour space the colour (chrominance) components have half the spatial resolution of the brightness (luminance) component.
Colour spaces which use a reduced amount of data to encode the colour components, such as YUV 420, are often used in consumer electronics and industrial applications. Colour space conversion can be performed where it is desired to convert content from one colour space to another colour space. For example, content can be up-sampled (upscaled) from a lower quality colour space (e.g. YUV 420) to a higher quality colour space (e.g. YUV 444).
Visual artifacts can occur when up-sampling content from a lower quality colour space to a higher quality colour space. This reduces the quality of the content that is presented to a user.